Monitoring sex and age ratios (i.e., population composition) is common practice in deer (Odocoileus spp.) management because these estimates are used to determine population vital rates, as well as assess effects of hunting regulations and other management actions. However, there is longstanding recognition of potential biases in sex and age ratios that can arise from differences in deer behavior and sightability, or from methodological issues, such as using roads for sampling. Biologists often use roads for composition surveys because of convenience and roads are often considered to provide coverage of the sampling area and, consequently, unbiased estimates of sex and age ratios. We tested the long‐standing belief that low‐use roads through mule deer (O. hemionus) winter range provided an unbiased sampling scheme by designing and conducting a random‐route survey in conjunction with the road survey through the same winter range in Round Valley, California, USA, during 2015 and 2016. In addition, we conducted a helicopter survey of the same area in 2016. We found adult male:adult female (buck:doe) ratios were 31–45% greater from the random‐route survey compared with the road survey. There was no difference in buck:doe ratios between road and helicopter surveys, but the random‐route survey had 55% greater buck:doe ratios than the helicopter survey. The helicopter survey also had 2.2–4.7 times greater proportions of unclassified bucks than the road or random‐route surveys. There were no differences in fawn:doe ratios among the 3 survey methods. We conducted additional spatial analyses to determine if the buck:doe ratio was greater along random‐routes because bucks were avoiding roads or because the random‐route survey covered different areas. We found that bucks were not avoiding roads; rather, the roads did not adequately cover the winter range area. There were differences between all 3 methods, but our main message is that the assumption that roads provide adequate coverage of winter range and unbiased estimates of population composition should be evaluated. To evaluate that assumption, we recommend conducting ≥1 survey using random routes and comparing composition estimates with road surveys. Further, if information on buck antler‐class is required for management decisions, a ground survey is preferable to a helicopter survey. © 2020 The Wildlife Society.

中文翻译：

---

偏向公路或直升机的M鹿成分调查？实地经验

在鹿（Odocoileus spp。）的管理中，监视性别和年龄比（即种群组成）是常见的做法，因为这些估计值用于确定种群的生命率，以及评估狩猎法规和其他管理措施的效果。但是，人们长期以来一直认识到，性别和年龄比例的潜在偏差可能是由于鹿的行为和可见度的差异，或者是由于方法问题（例如使用道路进行采样）引起的。由于便利，生物学家经常使用道路进行成分调查，并且通常认为道路可以覆盖采样区域，因此可以无偏估计性别和年龄比率。我们测试了长期以来的信念，即通过O鹿（O. hemionus）冬季范围通过在2015年至2016年期间设计和进行随机路线调查，并与美国加利福尼亚州Round Valley的同一冬季范围内的道路调查相结合，提供了一种无偏见的抽样方案。此外，我们还对与2016年相同，我们发现随机路线调查的成年男性与成年女性（buck：doe）比率比道路调查高出31–45％。道路调查和直升机调查之间的buck：doe比率没有差异，但是随机航线调查的buck：doe比率比直升机调查高55％。直升机调查的未分类收入比例也比公路或随机路线调查高出2.2-4.7倍。三种调查方法之间的小鹿：母鹿比率没有差异。我们进行了额外的空间分析，以确定是否可以降压：由于雄鹿避开了道路，或者随机路线调查涵盖了不同区域，因此沿随机路线的母鹿比率更高。我们发现，雄鹿并没有避开道路。相反，道路没有充分覆盖冬季范围。三种方法之间都存在差异，但是我们的主要信息是，应该评估道路能够充分覆盖冬季范围和对人口构成进行无偏估计的假设。为了评估该假设，我们建议使用随机路线进行≥1次调查，并将构成估算值与道路调查进行比较。此外，如果管理决策需要有关鹿角级的信息，则地面调查比直升机调查更可取。©2020野生动物协会。